How to create a date range in boost datetime? - c++

Question

I would like to create a range of timestamps, between a start date and end date and a chosen frequency. For example given these parameters as start date, end date and the frequency:
2002-01-20 23:59:59.000
2002-01-21 04:59:59.000
Freq = Hour
It should return a vector/list of timestamps:
2002-01-21 00:00:00.000
2002-01-21 01:00:00.000
2002-01-21 02:00:00.000
2002-01-21 03:00:00.000
2002-01-21 04:00:00.000
Does the Boost:date_time library have a function to achieve this?

Answer 1

Boost has two related things:
time_period
time iterators
The first literally gives you a date-range. The second is what you were looking for I think.
time_period:
Sample:
#include "boost/date_time/posix_time/posix_time.hpp"
#include <iostream>
using namespace boost::posix_time;
using namespace boost::gregorian;
struct day_period : time_period {
day_period(date d) : time_period(ptime(d), ptime(d, hours(24))) {}
};
int main() {
const date d(2002, Feb, 1); // an arbitrary date
const day_period dp(d); // the containing day
ptime t(d, hours(3) + seconds(5)); // an arbitray time on that day
if (dp.contains(t)) {
std::cout << to_simple_string(dp) << " contains " << to_simple_string(t) << std::endl;
}
// a period that represents part of the day
time_period part_of_day(ptime(d, hours(0)), t);
// intersect the 2 periods and print the results
if (part_of_day.intersects(dp)) {
time_period result = part_of_day.intersection(dp);
std::cout
<< to_simple_string(dp) << " intersected with\n"
<< to_simple_string(part_of_day) << " is \n"
<< to_simple_string(result) << std::endl;
}
}
Prints
[2002-Feb-01 00:00:00/2002-Feb-01 23:59:59.999999999]
contains 2002-Feb-01 03:00:05
[2002-Feb-01 00:00:00/2002-Feb-01 23:59:59.999999999]
intersected with
[2002-Feb-01 00:00:00/2002-Feb-01 03:00:04.999999999]
is
[2002-Feb-01 00:00:00/2002-Feb-01 03:00:04.999999999]
Time Iterators
Sample:
#include "boost/date_time/posix_time/posix_time.hpp"
#include <iostream>
int main() {
using namespace boost::gregorian;
using namespace boost::posix_time;
ptime start(date(2000, Jan, 20)), end = start + hours(1);
time_iterator titr(start, minutes(15)); // increment by 15 minutes
// produces 00:00:00, 00:15:00, 00:30:00, 00:45:00
while (titr < end) {
std::cout << to_simple_string(*titr) << std::endl;
++titr;
}
std::cout << "Now backward" << std::endl;
// produces 01:00:00, 00:45:00, 00:30:00, 00:15:00
while (titr > start) {
std::cout << to_simple_string(*titr) << std::endl;
--titr;
}
}